Bugger it worked yesterday!  Looks like windowsvista.com has closed it’s doors to selected unlucky people (myself included).

Now when I visit the pages and try to testdrive, I get this error:

Thank you for your interest in the Windows Vista Business test drive.

This trial program is available in limited geographies and languages,
and you are currently located outside of the available area.

Please check http://www.windowsvista.com for other Windows Vista
information and experiences that may be available to you.
 

My regional settings are English USA, so I assume it’s a geographic thing.  I do hope they re-open the labs to us soon, and that this valuable resource doesn’t stay a US only thing.